Quercus II

As promised more on oaks. One the first of Dec I bliped just a collection of "red oak group" leaves. This time I have both representatives of the red and white oaks.

I picked these leaves up at both work and in the neighborhood. Hilltop neighborhood in Denver is rather rich in oaks for Denver. All the leaves pictured are native to Eastern North American minus the Quercus robur, top middle row

Oaks in North America can be divided into roughly 2 groups red and white, just like wine. The top row are some examples of "white oaks" with their rounded leaf tips. The bottom rows are the "red oaks" with their pointed leaf tips.

The genus Quercus is found throughout the northern hemisphere with centers of diversity in Southeartern Asia (In Asia there are oaks outside the red or white groups) and North America including Mexico.

Oaks are notorious for hybridizing with related species and many oaks in the wild, especially on the edges of their ranges have hybrid influences. For this reason it can be almost impossible to determine the true identity of an oak. To make things worse the leaves can vary on the plants themselves. This carries over into cultivation and is the reason I don't have names assigned to the leaves in the right hand corner. They could be good old common Querucs rubra, rarer Quercus velutina, coccinea, or even shumardii or any combo. Oaks push the idea of a true species in the human eye. Many plants don't fit nicely into the traditional species package and can tend to integrate into one another at the edges of their native ranges

In the Copper Canyon region of Mexico where I was in the fall of 2009, the oaks were all evergreen some with leaves up to 12 inches long. The diversity there was amazing, and many hybrids were present.